Obesity rates in the U.S. are still rising, according to a new health study that says obesity rates increased in 28 states last year.

Two-thirds of the states have adult obesity rates above 25 percent and eight states have obesity rates over 30 percent.

The survey also says that 84 percent of parents believe their children are at a healthy weight. But nearly a third of American children and teens are actually considered obese or overweight.

"This report shows that the country has taken bold steps to address the obesity crisis in recent years, but the nation's response has yet to fully match the magnitude of the problem," said Jeffrey Levi, executive director of the Trust for America's Health, which writes the annual report with the Robert Wood Johnson Foundation.

In 2009, four states -- Mississippi, Alabama, Tennessee, and West Virginia had obesity of over 30 percent. This year, over eight states now have rates over 30 percent, including Louisiana, Kentucky, Oklahoma, and Arkansas.